Heat exchange unit



March 19, 1946. p Q HANNAH HEAT EXCHANGE UNIT Filed Sept 16 Patented Ma,19, 1946 UNITED STATES PATENT OFFICE HEAT EXCHANGE UNIT Perry C. Hannah,Dayton, Ohio, assignor to United Aircraft Products, Inc., Dayton, Ohio,a

corporation of Ohio Application September 16, 1943, Serial No. 502,660

Claims This invention relates to heat exchange units, such as are usedfor cooling the lubricating oil of aircraft and other internalcombustion engines, and has particular reference to improvements in thecore assembly for heat exchange units of the type disclosed in Dykemanet al. Patent No. 1,864,-

In heat exchange units of the type referred to,

the tubes usually extend longitudinally through the casing from end toend thereof; at their ends the tubes are usually soldered or otherwisesuitably fastened together and to the casing so as to close the ends ofthe latter. Between their ends said tubes are slightly spaced apart toprovide therebetween a maze of narrow passageways through which thefluid to becooled or heated flows in its passage through the casing.Moreover, the casing is provided with an inlet and an outlet usuallythough not necessarily located at substantially opposite points, andalso with a series of longitudinally extending, spaced apart partitionsdefining a tortuous passageway extending therethrough between the inletand the outlet thereof so that the fluid to be cooled or heated isrequired to flow along the outsides of substantially all of the tubesand throughout the effective lengths thereof in heat exchangerelationship with the latter during its passage through the casingbetween said inlet and said outlet.

The end portions of the tubes usually are of enlarged, hexagonal form soas to fit flatly against the partitions and against one another and tohold the medial portions of the tubes spaced from the partitions andfrom each other. Moreover, the partitions usually are co-extensive inlength with the casing and extend from side to side thereof, beingunsupported except at their ends where they are confined between theenlarged end portions of the tubes while their sides are fastened to thecasing.

Particularly in connection with heat exchange units that are designedfor use onaircraft, lightness in weight is a prime constructionalconsideration. Therefore, the casing, the tubes and the partitions ofheat exchange units of the type under consideration usually areconstructed of material as thin and light as possible consistent withpossession of requisite strength. In this connection, if the partitionsare thin and unsupported except at their margins, they may be unstableand subject to sagging and fiexure under the pressure of the fluidcirculated through the casing,'with possibly early deterioration of theunit. Moreover, if the partitions'are not rigid in the unit assembly,they are of little or no benefit as braces for the casing to assist inpreserving the'form thereof, when the same is subjected to pressure.

Accordingly, the general object of the present I invention ,is toprovide a heat exchange unit of thetype under consideration in which thepartitions, even though they may be formed of thin material and eventhough they may therefore be inherently unstable, are effectivelysupported against fiexure to contribute toward a rigid structure andalso to serve effectively as braces to assist in preserving the form ofthe casing.

More particularly, the object of the invention is to utilize certain ofthe tubes or their equivalents to hold the partitions against fiexureand rigidly with respect to the casing so that, as compared withconventional units of the type under consideration, no additional partsare required to accomplish the purposes of the invention and no changesin manufacturing procedure nor additional expenses are involved inproducing the improved unit.

With the foregoing and other objects in view, which will become morefully apparent as the nature of the invention is better understood, thesame consists in a heat exchange unit of the type under considerationembodying the novel features of construction, combination and arrange-,

ment of parts as will be hereinafter more fully described, illustratedin the accompanying drawing and defined in the appended claims.

In the accompanying drawing, wherein like characters of reference denotecorresponding parts in related views,

Figure '1 is a central, vertical, longitudinal section through a heatexchange unit, constructed in accordance with one practical embodimentof the invention.

Figure 2 is a fragmentary end elevation of the unit;

Figure 3 Ba fragmentary perspective view of a partition supporting tubeelement of the unit, as shown in Figure 1;

Figure 4 is a fragmentary perspective view of a modified form ofpartition supporting element of the unit, and a Figure 5 is afragmentary perspective view of through said casing from end to endthereof and substantially filling the spaces between the partitions ll.

In the bottom of the casing I. is an opening I! for inlet of fluidthereto and in the top of said casing is an opening ll for outlet offluid therefrom, while in alternate of the partitions ll, adjacent toone end of the casing. are openings ,l I and in the remaining alternatepartitions, adjacent to the other end of the casing, are openings l8.Accordingly, the spaces or passes between the partitions II are incommunication with each other through the partition openings I5 and I6and said spaces or passes, in conjunction with said partition openings,collectively constitute a single, continuous passageway extendingthrough the casing successively in op- .posite directions from end toend thereof and progressively from bottom to top thereof. It follows,therefore, that fluid admitted to the casing through the inlet openingsll is required to flow first in one direction and then in the oppositedirection and so on through the casing from end to end thereof before itcan escape therefrom through the outlet opening I.

Most of the tubes II have enlarged end portions of hexagonal shape incross section and medial portions of cylindrical or other suitable formin cross section and of lesser cross sectional area than their hexagonalend portions. The flat faces of the enlarged end portions ll of thesetubes engage flatly against one another in honeycomb fashion wherebytheir medial portions of lesser cross sectional area than their endportions are held spaced apart to provide therebetween a maze of narrowspacesthrough which fluid circulated through the casing may 'ilow.Moreover, the enlarged end portions of such of said tubes as aredisposed directly adjacent to the partitions II have their flat facesnearer said partitions engaged flatly against said partitions wherebytheir medial portions are held spaced from said partitions. In thisconnection, the partitions may be either flat or corrugated, butpreferably they are longitudinally corrugated as shown to best interfitat their ends with the said enlarged hexagonal end portions of thetubes.

At points where the enlarged end portions ll of the tubes l2 do not fltclosely against the easing 10, suitable filler pieces ll are employed toclose the voids between said enlarged end portions and the casing.Moreover, the enlarged end porticnsof the tubes and said flller piecesare soldered to one another and to the partitions and the casing so asto close the ends of the narrow spaces between said tubes and thepartitions and the casing.

As thus far described, the unit is of conventional construction with thepartitions ll unsupa,sce,oso

to the casing l0. It is manifest, therefore, that in a conventional unitthe partitions are free to flex and sag and, consequently, detract fromdesired rigidity of the unit and fail to act effectively as bracestoassist in preserving the form of the casing l0, all or which is quiteundesirable.

Now, in accordance with the present invention,

not all of the tubes I! have enlarged end portions, or, in other words,medial portions which are of lesser cross sectional area than their endportions. 0n the contrary, certain of the tubes, designated as He, areof the same cross sectional size and shape throughout theirlengths or atleast at their ends and at one or more spaced points along the lengthsof their medial portions, as the enlarged hexagonal end portions ll ofthe first mentioned tubes, and these tubes l2a are located at pointsdirectly adjacent to the partitions ii either to one side thereof asshown or, if desired, to both sides thereof. Therefore, not only the endportions, but also the medial portions of the tubes i211 engage thepartitions II and as a consequence said tubes 12a act effectively tohold the medial portions of said partitions against flexure or saggingwith the result that they are stable and rigid in the assembly and acteflectively as braces to assist in preserving the form of the casing ID.

If desired, all of the tubes that engage the partitions It may be of theform of the tubes l2a. This, however, is unnecessary and it is preferredto employ only a minor number of the tubes 12a in conjunction with anygiven partition, said tubes 12a being employed at suitably spaced apartintervals sufiicient to afford the desired support for the partitionsand the spaces between them being occupied by tubes of the form of thetubes if to afford spaces between the same and the partitions.

Preferably the tubes I20, are somewhat heavier, stiffer and strongerthan the tubes I 2, particularly if the latter tubes are thin andflexible, but,

of course, the tubes lZa may be formed from the same stock or they mayeven be formed from lighter stock than the tubes 12 if desired, the onlyessential being that they be amply still! and strong so as toeffectively support the medial portions of the partitions againstflexure or sagging.

If desired, the tubes 1211, instead of being of one-piece construction,may be composed of two or more mating sections no as illustrated in Fiure 4, this construction contributing toward economicai production incertain instances.

.The sections [2b ma be of semi-hexa onal form in cross section andeach-section may be a complete tube in itself as shown, the adjacentwalls of the two sections, when said sections are mated to provide ineffect a tube of hexagonal shape in cross section, constituting a beamto afford firm support for the partition element.

Also, solid rods I20 as illustrated in Figure 5 may be used in lieu ofthe tubes Ila if desired, and these rods may be either of one piece orof mating section construction.

Oil or other fluid or liquid to be cooled or heated is required by thepartition -H to flow in a tortuous path through the casing in along andbetween the tubes |2 and l2a or equivalently, the rods I20 substantiallythroughout the lengths thereof, and as will of course be understood, themedium, such as air, for cooling or heating the oil or other fluid flowsthrough the tubes 12, Ila in effective heat exchange relationship of thefluid to be cooled or heated. A

While the casing It, the partitions H and the tubes l2 have beenillustrated and described as disposed horizontally, it will beunderstood of course that the unit may be used in any desired positionand that the appended claims are to be construed accordingly.

From the foregoing description considered in connection with theaccompanying drawing it is believed that the novel constructionalfeatures of the invention will be clearl understood and their advantagesappreciated. It is desired to point out, however, that while onlycertain constructional forms of the invention have been illustrated anddescribed, th same may readily be embodied in various specificallydifferent constructional forms within the spirit and scope as defined inthe appended claims.

What is claimed is:

1. A heat exchange unit comprising a casing having an inlet and anoutlet for a fluid to be circulated therethrough, a multiplicity ofparallel heat exchange elements substantially filling said casing andextending substantially from end to end thereof, at least one partitionin said casing being substantially parallel to said elements andextending from side to side and substantially from end to end of saidcasing and requiring the fluid circulated through said casing to followa tortuous path therethrough in heat exchange relationship to saidelements substantially throughout the lengths thereof, certain of saidelements having enlarged end portions abutting one another and saidpartition to space the medial portions thereof from one another and fromsaid partition, other of said elements being composed of separate matingsections and being of the same size throughout their lengths as theenlarged end portions of said first mentioned elements and having theirend portions abutting said enlarged end portions of said first mentionedelements and their medial portions disposed in contacting sup- 40porting relationship with said partition, and means fastening the endportions of said elements together and to said casing and said partitionto close the ends of thecasing, certain of said elements being oftubular form for fiow therethrough of a fluid medium in heat exchangerelationship to the fluid circulated through said casing.

2. A core section for a heat exchange unit or like device, comprising anassembly of elongated tubes, said assembly being partitioned by a bailiewhich extends longitudinally through the assembly, said assembly oftubes including a first type having ends which are expanded with respectto the medial body portions thereof and which are in engagement with theends of adjacent tubes, the expanded ends of some of the tubes of saidfirst type further engaging respective ends of said bailie thereby toprovide limited support for the baiile, and said assembly of tubesfurther includ-. .0

ing tubes of a second type having the same cross sectional area.throughout their lengths, the ends of said second type tubes beingnested among the expanded ends of the tubes of said first type and themedial portions of the tubes of said second type being in continuouscontact with the battle, whereby to provide a support for said baflleintermediate its ends.

3. A core section for a heat exchange unit or like device, comprising anassembly of elongated tubes, said assembly being partitioned by a baillewhich extends longitudinally through the assembly and is approximatelyco-extensive in length with said tubes, said assembly of tubes beinggrouped with their ends in nested relation and including tubes of firstand second types, some of said first and second types of tubescontacting and supporting said baiile, the tubes of said first typehaving ends expanded with respect to their medial body portions wherebythose in contact with said battle provide support therefor only at theends of the baflle, and the tubes of said second type having thesamecross sectional area throughout their lengths whereby continuouscontact with said baffle all along the length thereof is enabled andsupport provided for the baille from end to end thereof.

4. A heat exchange unit of the character described including a casinghaving an inlet and an outlet, a plurality of spaced partitions in saidcasing extending from end to end and side to side thereof and formed tocause liquid in the easing to flow in a tortuous path between the inletand outlet, a multiplicity of open ended heat exchange elements disposedwithin said casing between said partitions, said element having enlargedends and reduced medial portions so as to permit the fiow of liquidaround the latter, said elements having their enlarged end portions incontacting relation with each other and with the partitions, and meansfor engaging and supporting said partitions, said means having a uniformdiameter throughout their entire length substantially equal to thediameter of the enlarged ends of the heat exchange elements so as tointerfit therewith.

5. A heat exchange unit of the character described including a casinghaving an inlet and an outlet, a plurality of spaced partitions in saidcasing disposed so as to cause liquid flowing through the casing tofollow a tortuous path between the inlet and outlet thereof, a pluralityof spaced supporting members disposed beneath and engaging saidpartitions, said members being substantially hexagonal in cross-sectionand of a uniform size throughout their lengths, and a plurality ofopen-ended heat exchange element disposed within said casing betweensaid partitions and supporting members, said heat exchange elementshaving enlarged hexagonal shaped ends interfitting with each other andwith the supporting members adjacent the ends of the latter and reducedmedial portions so as to provide a passage around adjacent elements forliquid flowing through the casing from the inlet to the outlet thereof.

' PERRY c. HANNAH.

